This invention generally relates to hydraulic actuators and more particularly to a disk brake actuator as may be applied to aircraft type disk brake assemblies.
Disk brake assemblies of the type alluded to are conventionally full circle configurations which incorporate at least two piston actuators in a balanced arrangement about the circle and which operate to move a pressure plate into engagement with a disk brake stack comprised of alternating stationary and rotating disk elements. The piston actuators conventionally operate under the influence of a single hydraulic pressure, and in systems wherein it is desired to provide emergency and/or parking brake capabilities these are provided by separate hydraulic and/or mechanical apparatus.
This invention provides, within a single actuator, both a high pressure and a low pressure actuating capability without affecting the deceleration ability of a disk brake system. The invention also eliminates the need for separate emergency and/or parking brake mechanisms and thus eliminates the additional weight of these separate apparatus. The present invention further provides a manual low pressure back-up braking capability without degrading the overall braking performance of the system. While the invention is described with respect to an aircraft disk brake application, it is not limited to such application but may be applied to any application wherein a dual pressure actuation is desired.